Making maps is fairly easy once you get used to it. And the PvP code is a one-time thing once you get it working. You can increase the amount of maps to include more than one map to have PvP in it. Most of the maps people give away for free are more wildlife, realistic, or fantasy like maps, forests, meadows, lava-y places, etc. So you're better off making your own map/commissioning one if you want an arena/battle map.